1. Field of the Invention
The present invention relates to micro-analytic technologies, more particularly to an apparatus for extracting TEM specimens of semiconductor devices.
2. Description of the Prior Art
Micro-analytic technologies have been used in a wide range of applications in IC industry. The tolerance for defect size in IC wafer is limited more than ever, and the ability of micro-analytic apparatus should be enhanced. In general, micro-analytic apparatus is used for aspect analysis and composition analysis. For aspect analysis, transmission electron microscope (TEM) can provide information about phase contrast, atomic lattice imaging and others. The TEM specimens are easy to prepare, and developed day after day.
The new technology for preparing TEM specimen is disclosed by FEI company, and described below summarily:
(1). The wafer or die based navigation software in the FIB is used to locate a specific defect site. The other processes involve dicing the wafer, mechanically polishing the sliced specimen. PA1 (2). The focused ion beam (FIB) is used for final thinning to form the specimen which is 10 .mu.m long, 0.2 .mu.m thick, and 8 .mu.m deep. PA1 (3). Under both a TEM specimen extractor and an optical microscope (OM), a specimen is extracted and removed from the wafer by electrostatic attraction existing on the tip of a pipette fixed on the TEM specimen extractor. Finally, the specimen is dropped on the grid, and then TEM is subsequently used to analyze the specimen.
A probe station primarily used as an electroscope is converted into the TEM specimen extractor which is described above and has a very high price. In the TEM specimen extractor, 5 rotary buttons, of which 3 are for coarse adjustments in X, Y, Z directions and 2 are for fine adjustments in X, Y directions, are used to control movement of the pipette. Therein, to move the pipette in the same direction, a coarse and a fine rotary button should be turned respectively in the opposite direction. The complicated manipulation usually causes failure in extracting. In fact, the pipette, of which diameter of tip side is about 2 .mu.m, usually breaks when it touches the wafer. That's due to wrong direction or too many adjustments. In addition, the wafer is also damaged. For the reason described previously, an operator should be given a long-time training. Moreover, the driving device of the extractor, the assemblage of gears and chains, will give the extractor lower accuracy about locating ability after used for a few times. Therefore, practicability of the extractor will be also reduced.
For the foregoing reasons, there is a need to develop an extracting apparatus which provides a lower price, easier manipulation, and high success rate of extracting.